In the application of MSI and LSI integrated circuit (IC) components, the IC device must be electrically connected to its associated circuitry. Two methods are commonly applied.
A first method involves direct mounting to a printed circuit (PC) board where each terminal of the IC is soldered to the circuit pattern. This method is least costly, allows high packaging density and provides high reliability.
A second method involves an intermediate component referred to as a connector or socket, having a corresponding number and terminal arrangement as the IC employed. The intermediate connector is permanently soldered to the printed circuit board and the IC is plugged into the connector. Electrical connection of the IC to the PC board circuit is invariably achieved through spring contacts in the intermediate connector. Each spring contact includes a prong which extends beyond the base of the intermediate connector. The prong portions of the spring contacts enter the holes in the PC board and are soldered to the circuit pattern. The use of the intermediate connector is advantageous due to the ease of replacing a defective IC and, in trouble shooting, of replacing a suspected defect with a funcationally good unit. The cost of the socket is offset by the savings that arise from the rapid repair made possible.
Today's trend is toward the intermediate connector approach. Replacement and service are made easier and quicker. Despite the cost of the added socket economics favor this method. However, unless the intermediate connector possesses the required physical and electrical characteristics equipment reliability can be adversely affected.
Accordingly, the major purpose of this invention is to provide an intermediate connector for use between an PC board and an IC circuit; the connector having an optimum combination of ease of repair, ease of assembly and reliability characteristics.
More specifically, the purposes of this invention are to provide an intermediate connector that will maintain contact and stability under vibration and shock, that will avoid localized high spots in the connection between IC terminal and connector, that will provide a low contact resistance and that will provide a relatively high contact force coupled with a relatively low insertion force.
It is a further purpose of the invention to achieve the above purposes in combination with minimum degredation of the characteristics under repeated withdrawal and insertion of the IC circuit.
As is usually the case, it is an important purpose of this invention to provide all of the above characteristics in a context that has long life, requires minimum maintenance, is simple in design and has low costs in manufacture. These objectives are achieved by a specific design approach and invention as set forth in detail below.